A virtual acoustic system is one that gives the user the illusion that sound is emanating from elsewhere in an indoor or outdoor space than directly from a loudspeaker (e.g., one that is placed in a room, one that is built into a laptop computer, etc. Audio signal processing for virtual acoustics can greatly enhance a movie, a sports even, a videogame or other screen viewing experience, adding to the feeling of “being there”. Various known audio processing algorithms, executed by digital processors, modify one or more recorded, synthesized, mixed or otherwise produced digital audio signals in such a way as to position a virtual source according to modeling that is based on human perception of sound, including the role of ear acoustics, other reflecting and absorbing surfaces, distance and angle of source, and other factors. In the case of headphones, specially processed audio signals (binaural rendering) are sent to left and right ears of a listener without the crosstalk that is inevitably received by the ears when listening to stereo loudspeakers. For viewers and listeners that prefer loudspeakers, for example those that may be built into a laptop computer, a crosstalk canceler is employed in some virtual acoustic systems to produce sounds from multiple loudspeakers in such a way that for example a “left” audio signal is predominantly heard only at the left ear of the listener, and a “right” audio signal is predominantly heard only at the right ear of the listener (by virtue of sound wave cancellation in the air surrounding the listener.) This allows the left and right audio signals to contain spatial cues that enable a virtual sound to be “positioned” at a desired location between the loudspeakers.